<!DOCTYPE html>
<html lang="en">

<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
    <style>
        div {
            cursor: pointer;
        }
    </style>
</head>

<body>
    <script>
      let a={a:1,b:2}
      let b={a:3,b:''}
    let c=Object.assign(a,b)
// let c={...a,...b}

    console.log(c);


    </script>
</body>

</html>